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Old 08-05-2019, 10:23 PM
vortalexfan vortalexfan is offline
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Join Date: Sep 2018
Location: Northern Indiana
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Quote:
Originally Posted by Electronic M View Post
Even bottom of the barrel cheap mid-late 30's AA5s had AVC, but in the early 30's it wasn't universal yet. It was typically derived from the detector or a second diode plate in the detector tube (which was the reason why tubes like the 6AV6 and 6SQ7 had 2 extra diode plates instead of on just one).

If there is no AVC or defective AVC the volume will vary widely in step with RF carrier strength...Ever operate a working 1920's TRF circuit based receiver? TRFs almost always lack AVC and with the volume cranked to 11 they will struggle to put out enough volume to listen on a distant or low power station but blow your eardrums out on a strong local...Superhet sets can act the same without AVC.
Let me study up on the schematic for this radio again and see if it does actually have AVC on it. If it does I would be awfully shocked that it does, and I'll have to figure out which of the 3 tubes for the tuner section is powering the AVC circuit and try subbing out tubes.
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